pytest是python中较常用的测试框架，官方文档见：

https://docs.pytest.org/en/stable/contents.html#toc

安装命令：

pip install -U pytest

检查是否安装成功命令：

pytest --version

能查到版本号说明安装OK，否则嘿嘿。

创建第一个测试脚本test_sample.py：

# content of test_sample.py
def func(x):
    return x + 1


def test_answer():
    assert func(3) == 5

通过命令pytest执行，得到结果如下：

$ pytest
=========================== test session starts ============================
platform linux -- Python 3.x.y, pytest-6.x.y, py-1.x.y, pluggy-0.x.y
cachedir: $PYTHON_PREFIX/.pytest_cache
rootdir: $REGENDOC_TMPDIR
collected 1 item

test_sample.py F                                                     [100%]

================================= FAILURES =================================
_______________________________ test_answer ________________________________

    def test_answer():
>       assert func(3) == 5
E       assert 4 == 5
E        +  where 4 = func(3)

test_sample.py:6: AssertionError
========================= short test summary info ==========================
FAILED test_sample.py::test_answer - assert 4 == 5
============================ 1 failed in 0.12s =============================

跟Junit测试框架类似都有assert的方法来对比实际结果和预期的结果是否一致，如果不一致则返回F，并指出错误的位置。